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// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef MOJO_SERVICES_VIEW_MANAGER_PUBLIC_CPP_VIEW_PROPERTY_H_
#define MOJO_SERVICES_VIEW_MANAGER_PUBLIC_CPP_VIEW_PROPERTY_H_
#include <stdint.h>
// This header should be included by code that defines ViewProperties. It
// should not be included by code that only gets and sets ViewProperties.
//
// To define a new ViewProperty:
//
// #include "components/view_manager/public/cpp/view_property.h"
//
// DECLARE_EXPORTED_VIEW_PROPERTY_TYPE(FOO_EXPORT, MyType);
// namespace foo {
// // Use this to define an exported property that is premitive,
// // or a pointer you don't want automatically deleted.
// DEFINE_VIEW_PROPERTY_KEY(MyType, kMyKey, MyDefault);
//
// // Use this to define an exported property whose value is a heap
// // allocated object, and has to be owned and freed by the view.
// DEFINE_OWNED_VIEW_PROPERTY_KEY(gfx::Rect, kRestoreBoundsKey, nullptr);
//
// // Use this to define a non exported property that is primitive,
// // or a pointer you don't want to automatically deleted, and is used
// // only in a specific file. This will define the property in an unnamed
// // namespace which cannot be accessed from another file.
// DEFINE_LOCAL_VIEW_PROPERTY_KEY(MyType, kMyKey, MyDefault);
//
// } // foo namespace
//
// To define a new type used for ViewProperty.
//
// // outside all namespaces:
// DECLARE_EXPORTED_VIEW_PROPERTY_TYPE(FOO_EXPORT, MyType)
//
// If a property type is not exported, use DECLARE_VIEW_PROPERTY_TYPE(MyType)
// which is a shorthand for DECLARE_EXPORTED_VIEW_PROPERTY_TYPE(, MyType).
namespace mojo {
namespace {
// No single new-style cast works for every conversion to/from int64_t, so we
// need this helper class. A third specialization is needed for bool because
// MSVC warning C4800 (forcing value to bool) is not suppressed by an explicit
// cast (!).
template <typename T>
class ViewPropertyCaster {
public:
static int64_t ToInt64(T x) { return static_cast<int64_t>(x); }
static T FromInt64(int64_t x) { return static_cast<T>(x); }
};
template <typename T>
class ViewPropertyCaster<T*> {
public:
static int64_t ToInt64(T* x) { return reinterpret_cast<int64_t>(x); }
static T* FromInt64(int64_t x) { return reinterpret_cast<T*>(x); }
};
template <>
class ViewPropertyCaster<bool> {
public:
static int64_t ToInt64(bool x) { return static_cast<int64_t>(x); }
static bool FromInt64(int64_t x) { return x != 0; }
};
} // namespace
template <typename T>
struct ViewProperty {
T default_value;
const char* name;
View::PropertyDeallocator deallocator;
};
template <typename T>
void View::SetLocalProperty(const ViewProperty<T>* property, T value) {
int64_t old = SetLocalPropertyInternal(
property, property->name,
value == property->default_value ? nullptr : property->deallocator,
ViewPropertyCaster<T>::ToInt64(value),
ViewPropertyCaster<T>::ToInt64(property->default_value));
if (property->deallocator &&
old != ViewPropertyCaster<T>::ToInt64(property->default_value)) {
(*property->deallocator)(old);
}
}
template <typename T>
T View::GetLocalProperty(const ViewProperty<T>* property) const {
return ViewPropertyCaster<T>::FromInt64(GetLocalPropertyInternal(
property, ViewPropertyCaster<T>::ToInt64(property->default_value)));
}
template <typename T>
void View::ClearLocalProperty(const ViewProperty<T>* property) {
SetLocalProperty(property, property->default_value);
}
} // namespace mojo
// Macros to instantiate the property getter/setter template functions.
#define DECLARE_EXPORTED_VIEW_PROPERTY_TYPE(EXPORT, T) \
template EXPORT void mojo::View::SetLocalProperty( \
const mojo::ViewProperty<T>*, T); \
template EXPORT T mojo::View::GetLocalProperty(const mojo::ViewProperty<T>*) \
const; \
template EXPORT void mojo::View::ClearLocalProperty( \
const mojo::ViewProperty<T>*);
#define DECLARE_VIEW_PROPERTY_TYPE(T) DECLARE_EXPORTED_VIEW_PROPERTY_TYPE(, T)
#define DEFINE_VIEW_PROPERTY_KEY(TYPE, NAME, DEFAULT) \
COMPILE_ASSERT(sizeof(TYPE) <= sizeof(int64_t), property_type_too_large); \
namespace { \
const mojo::ViewProperty<TYPE> NAME##_Value = {DEFAULT, #NAME, nullptr}; \
} \
const mojo::ViewProperty<TYPE>* const NAME = &NAME##_Value;
#define DEFINE_LOCAL_VIEW_PROPERTY_KEY(TYPE, NAME, DEFAULT) \
COMPILE_ASSERT(sizeof(TYPE) <= sizeof(int64_t), property_type_too_large); \
namespace { \
const mojo::ViewProperty<TYPE> NAME##_Value = {DEFAULT, #NAME, nullptr}; \
const mojo::ViewProperty<TYPE>* const NAME = &NAME##_Value; \
}
#define DEFINE_OWNED_VIEW_PROPERTY_KEY(TYPE, NAME, DEFAULT) \
namespace { \
void Deallocator##NAME(int64_t p) { \
enum { type_must_be_complete = sizeof(TYPE) }; \
delete mojo::ViewPropertyCaster<TYPE*>::FromInt64(p); \
} \
const mojo::ViewProperty<TYPE*> NAME##_Value = {DEFAULT, \
#NAME, \
&Deallocator##NAME}; \
} \
const mojo::ViewProperty<TYPE*>* const NAME = &NAME##_Value;
#endif // MOJO_SERVICES_VIEW_MANAGER_PUBLIC_CPP_VIEW_PROPERTY_H_
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